A printer or copier typically has a strike plate that a leading edge of a printed sheet contacts as it exits the printing machine, thereby halting the forward momentum of the sheet and aligning the sheet so that it falls, properly aligned, into a receiving tray.
FIGS. 1A and 1B are schematic rendition of an exit section 100 of a printer or other device (not shown). After printing is completed, a printed sheet 150 moves in a direction 152 and a leading edge 170 contacts a strike plate 180. Strike plate 180 serves to stop further motion of sheet 150 in direction 152 and align sheet 150 so that it falls flat into a stack of printed sheets 140 and/or sheet a receiving tray 102.
When a sheet 150 hits plate 180, ideally, the sheet should fall onto a tray 102, completely aligned in both the forward and cross directions. Since sheets may not fall directly on each other in the tray a surface 160 may be used to straighten the substrates and place them against a front surface of the tray. Similar mechanisms may be employed to align the sheets in the cross direction.
However, when sheets 150 hit strike plate 180 they may not just stop and fall into place. Often, especially with light weight sheets, the sheets will curl down (FIG. 1A) or up (FIG. 1B). If the curl is large enough, the jogging will not be sufficient to both straighten and align the sheet and the sheet.
U.S. Pat. No. 4,667,949 shows an angled strike plate at a trailing edge of the sheet. The object of this plate is to force the trailing edge of a sheet toward the pile of sheets as it ricochets from strike plate 180.